Many controlled release dosage forms have been developed for the delivery of pharmaceutical drugs for prolonging the release and absorption of the drug in the alimentary canal. Similarly, many methods and types of apparatus have been invented to produce such drugs. For example, U.S. Pat. No. 5,472,710 to Klokkers-Bethke et al., discloses a pharmaceutical preparation to be administered orally with controlled release of an active substance and a method for the manufacture of the preparation.
U.S. Pat. No. 6,669,954 to Crison et al., discloses devices for controlled release of drugs.
U.S. Pat. No. 6,685,962, to Friedman et al., discloses gastro-retentive controlled release pharmaceutical dosage forms.
U.S. Pat. No. 6,911,217 to Gren et al., discloses a controlled release bead, a method for producing the same and a multiple unit formulation comprising the bead.
WO 03/105812 A1 describes an extruded pharmaceutical product for retention in the stomach; comprising a sheet of hydratable polymer of a size that does not exit the stomach; a shaped sheet; a planar sheet that is rolled or folded or otherwise compacted; and a sealed hollow tubular extrudate.
WO 2005/009199 describes an automated process and apparatus for making a gastro retentive device, having a pouch assembly or capsule assembly.
Despite the numerous advances in the development of controlled release delivery formulations, there is a still a need to develop apparatus and methods for reliable mass production of agent delivery formulations.